Final Cut Pro Progressive/interlaced conversion?

Hello
I have what I hope is a simple question.
I'm a freelance video journo working in Africa - I use a Sony Z7 and recently was told by a European client that they couldn't accept my footage because it was filmed in progressive and they need interlaced.
I checked the camera settings and I indeed filmed on progressive (Scan Type 50). I thought I always used this as haven't changed any settings on the camera.
Is anyone able to enlighten me please on a) if the setting is incorrect and b) if it is - can it be converted to interlaced?
Have I been filming incorrectly by using progressive scan type 50 - should it be 25?
Thank you so much, Anna Little

The Sony Z7 doesn't record 720p but does 1080p. 1080p25 "fits" in 1080i50 just fine so it's odd they require 1080i. The future off broadcast is web and tablet devices which only supports progressive formats. Requiring interlace is very short sighted.

There's really no good way of converting 25p to 50i. You are missing half the temporal info. The only way would using optical flow to create 50 images out of 25. That's a tall order. You can try it in Compressor, After Effects or Twixtor. If there is a lot of moving/crossing objects in your footage you will get image tearing and warping as it tries to morph new images.

Interesting they would want interlaced. I am an advocate of progressive as this shows up so much better on computers and LCD screens. In fact if you had shot interlaced then encoded it over to progressive, you would still likely have those artifacts of interlacing, the ringing, vibratory quality at the contrast edges and dark areas. And when encoding interlaced footage for the web, you're more likely to get step-casing with fast motions. Progressive is the general way to go with original footage in my opinion, depending on the level of the photographic needs, and to hand them interlaced footage, simply codec the footage over to interlaced for them using encoding software like Compressor or Episode or Squeeze. If you're a Mac person with FCP then simply bring the footage into a timeline and export it with custom interlaced settings. You should ask your client what editing or compositing software they are using and why they want to go interlaced. You might also ask them if they can handle progressive and codec it themselves.